Many types of pigments are used for various coating applications. For example, inorganic pigments such as TiO2, Fe2O3, Al2O3, MgO, CaO, ZnO, carbon black and aluminum silicate are often used in paints and other coatings. Such inorganic pigments typically have particle sizes ranging from about 0.5 to about 30 microns, and are made by processes such as flame processes, plasma processes, solution processes and sol-gel processes. For example, most commercial TiO2 is made using TiCl4 as a starting material. Pure TiCl4 is reacted with oxygen in an exothermic reaction to form titanium dioxide and to liberate chlorine, which is recycled to the chlorination stage. The high temperature ensures that only the rutile crystal form is produced. After cooling, the gas stream passes through a separator to collect the pigment particles, which are treated to remove adsorbed chlorine from the pigment.